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61.
Bigi A Bracci B Cuisinier F Elkaim R Fini M Mayer I Mihailescu IN Socol G Sturba L Torricelli P 《Biomaterials》2005,26(15):2381-2389
Octacalcium phosphate (OCP) and Mn(2+)-doped carbonate hydroxyapatite (Mn-CHA) thin films were deposited on pure, highly polished and chemically etched Ti substrates with pulsed laser deposition. The coatings exhibit different composition, crystallinity and morphology that might affect their osteoconductivity. Human osteoblasts were cultured on the surfaces of OCP and Mn-CHA thin films, and the cell attachment, proliferation and differentiation were evaluated up to 21 days. The cells showed a normal morphology and a very good rate of proliferation and viability in every experimental time. Alkaline phosphatase activity was always higher than the control and Ti groups. From days 7 to 21 collagen type I production was higher in comparison with control and Ti groups. The level of transforming growth factor beta 1 (TGF-beta1) was lower at 3 and 7 days, but reached the highest values during following experimental times (14 and 21 days). Our data demonstrate that both calcium phosphate coatings favour osteoblasts proliferation, activation of their metabolism and differentiation. 相似文献
62.
Koppelstaetter C Jennings P Hochegger K Perco P Ischia R Karkoszka H Mayer G 《Mechanisms of ageing and development》2005,126(12):1331-1333
Telomere length is a well established marker of cellular senescence and thus biological age. Quantitative PCR allows the determination even from very low amounts of tissue by using telomere specific and single copy gene primers. Comparing a directly processed tissue sample to a 4% formaldehyde fixed one showed a significantly reduced efficiency of PCR reactions (mainly in single copy gene experiments) in a storage time-dependent manner resulting in an artificial increase in reported relative telomere length. This effect was not seen when the tissue was stored in RNA later solution. In summary, telomere length determination from formaldehyde fixed material by quantitative PCR is not a reliable method. Unfortunately therefore, many easily accessible tissue samples from pathology laboratories are unsuitable for this technique. 相似文献
63.
Matthias Löhle Thomas Müller Carola Wicher Marcus Roedel Harald Schubert Otto W. Witte Peter W. Nathanielsz Matthias Schwab 《The Journal of physiology》2005,564(2):575-588
Synthetic glucocorticoids are administered to pregnant women in premature labour to accelerate fetal lung maturation at a time when fetal cerebrovascular and endocrine systems are maturing. Exposure to glucocorticoids at 0.8–0.9 of gestation increases peripheral and cerebrovascular resistance (CVR) in fetal sheep. We examined whether the increase of CVR and its adverse effect on cerebral blood flow (CBF) depend on the current level of maturation of the pituitary–adrenal axis and the cerebrovascular system. Using fluorescent microspheres, regional CBF was measured in 11 brain regions before and 24 h and 48 h after the start of 3.3 μg kg−1 h−1 betamethasone ( n = 8) or vehicle ( n = 7) infusions to fetal sheep at 0.73 of gestation. Hypercapnic challenges were performed before and 24 h after the onset of betamethasone exposure to examine betamethasone effects on cerebrovascular reactivity. Betamethasone exposure decreased CBF by approximately 40% in all brain regions after 24 h of infusion ( P < 0.05). The decline in CBF was mediated by a CVR increase of 111 ± 16% in the cerebral cortex and 129 ± 29% in subcortical regions ( P < 0.05). Hypercapnic cerebral vasodilatation and associated increase in CBF were blunted ( P < 0.05). Fetal CBF recovered after 48 h of betamethasone administration. There were no differences in glucocorticoid induced CBF and CVR changes compared with our previous findings at 0.87 of gestation. We conclude that the cerebrovascular effects of antenatal glucocorticoids are independent of cerebrovascular maturation and preparturient increase in activity of the fetal pituitary–adrenal axis. 相似文献
64.
Zhu H Goodyear BG Lauzon ML Brown RA Mayer GS Law AG Mansinha L Mitchell JR 《Medical physics》2003,30(6):1134-1141
The Stockwell transform (ST), recently developed for geophysics, combines features of the Fourier, Gabor and wavelet transforms; it reveals frequency variation over time or space. This valuable information is obtained by Fourier analysis of a small segment of a signal at a time. Localization of the Fourier spectrum is achieved by filtering the signal with frequency-dependent Gaussian scaling windows. This multi-scale time-frequency analysis provides information about which frequencies occur and more importantly when they occur. Furthermore, the Stockwell domain can be directly inferred from the Fourier domain and vice versa. These features make the ST a potentially effective tool to visualize, analyze, and process medical imaging data. The ST has proven useful in noise reduction and tissue texture analysis. Herein, we focus on the theory and effectiveness of the ST for medical imaging. Its effectiveness and comparison with other linear time-frequency transforms, such as the Gabor and wavelet transforms, are discussed and demonstrated using functional magnetic resonance imaging data. 相似文献
65.
Clone-based systematic haplotyping (CSH): a procedure for physical haplotyping of whole genomes 总被引:4,自引:0,他引:4 下载免费PDF全文
Burgtorf C Kepper P Hoehe M Schmitt C Reinhardt R Lehrach H Sauer S 《Genome research》2003,13(12):2717-2724
We present a novel methodology to determine the phase of single-nucleotide polymorphisms (SNPs) on a chromosome, which we term clone-based systematic haplotyping (CSH). The CSH procedure is based on separating the allelic chromosomes of a diploid genome by fosmid/cosmid cloning, and subsequent SNP typing of 96 clone pools, each representing approximately 10% of the genome. The pools are screened by PCR for the sequence of interest, followed by SNP typing on the PCR products using the GOOD assay. We demonstrate that by CSH, the haplotype of SNPs separated by more than 50 kilobases can definitely be assigned. We propose this method as being suitable for constructing maps of ancestral haplotypes, analysis of complex diseases, and for diagnosis of rare defects in which the molecular haplotype is crucial. In addition, by amplifying the initial DNA by many orders of magnitude, the original DNA resource is effectively immortalized, enabling the haplotyping of hundreds of thousands of SNPs per individual. 相似文献
66.
Rapid titration of varicella-zoster virus (VZV) in human embryonic fibroblasts (HEF) based on staining of virus-infected cells by indirect immunoperoxidase technique (IPA) is described. Cell monolayers were grown in wells of plastic plates (two different diameters). Foci of virus-infected cells as revealed by IPA could be counted either 48 hr post-infection, if cell-associated virus (VZV infected cells) was used as inoculum, or 72 hr p. i. if cell-free virus was used. A linear relationship was observed between virus dilution and number of foci. The first virus was detected 12 hr p. i., the highest titre at 36 hr, when cytopathic effect (CPE) involved about 50% of the monolayer. 相似文献
67.
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69.
Microanatomical study of the arterial blood supply of the facial nerve in the ponto-cerebellar angle
Ph. Mercier P. Cronier B. Mayer J. Pillet G. Fischer 《Surgical and radiologic anatomy : SRA》1982,3(3):263-270
Summary The blood supply of 50 facial nerves was examined during a micro-anatomical study of the ponto-cerebellar angle using injections of colored latex or Chinese ink.The results indicate the presence of a double arterial blood supply: the proximal supply, rising at the level of the brain stem, results from the confluence of three to five arterioles originating from the anterior inferior cerebellar artery or from the basilar artery itself; the distal supply at the level of the internal acoustic meatus arises from the labyrinthine artery.These two arterial systems do not anastomose directly but by way of capillaries of less than 200 microns in diameter.From these findings the authors conclude that certain postoperative facial paralyses, which may arise in spite of the conservation of the nerve, are in fact ischemic in nature.
Etude micro-anatomique de la vascularisation artérielle du nerf facial dans l'angle ponto-cérébelleux
Résumé Dans le cadre d'une étude micro-anatomique de l'angle ponto-cérébelleux, la vascularisation de 50 nerfs faciaux est examinée sous microscope opératoire après injection au latex coloré ou à l'encre de Chine.Cette étude permet aux auteurs de décrire un double apport artériel: l'un proximal, né au niveau du tronc cérébral, résulte de la confluence de 3 à 5 artérioles issues de l'ACiA ou de l'artère basilaire ellemême; l'autre distal, au niveau du méat acoustique interne, provient de l'artère labyrinthique. Ces deux systèmes artériels ne s'anastomosent pas entre eux à plein canal, mais par des capillaires d'un diamètre inférieur à 200 microns.Les auteurs en tirent argument pour estimer que certaines paralysies faciales post-opératoires survenant malgré la conservation anatomique du nerf, sont de nature ischémique.相似文献
70.
Silvia Obenauer Christian Sohns Carola Werner Eckhardt Grabbe 《Journal of digital imaging》2006,19(3):258-263
The goal of this study was to evaluate the performance of a computer-aided detection (CAD) system in full-field digital mammography
(Senographe 2000D, General Electric, Buc, France) in finding out carcinomas depending on the parenchymal density. A total
of 226 mediolateral oblique (MLO) and 186 craniocaudal (CC) mammographic views of histologically proven cancers were retrospectively
evaluated with a digital CAD system (ImageChecker V2.3 R2 Technology, Los Altos, CA, USA). Malignant tumors were detected
correctly by CAD in MLO view in 84.85% in breasts with parenchymal tissue density of the American College of Radiology (ACR)
type 1, in 70.33% of the ACR type 2, in 68.12% of the ACR type 3, and in 69.70% of the ACR type 4. For the CC view, similar
results were found according to the ACR types. Using the chi-square and McNemar tests, there was no statistical significance.
However, a trend of better detection could be seen with decreasing ACR type. In conclusion, there seems to be a tendency for
breast tissue density to affect the detection rate of breast cancer when using the CAD system. 相似文献